|Quadrangle map, 1:250,000-scale||HE|
|Quadrangle map, 1:63,360-scale||D-3|
|Nearby scientific data||Find additional scientific data near this location|
|Location and accuracy||This prospect is at an elevation of about 700 feet near the head of Sheep Creek. It is in the NW1/4 of sec. 35, T. 11 S., R. 4 W., of the Fairbanks Meridian. The location is accurate to within 1 mile. This is locality 4 of Cox and others (1989).|
Geologic descriptionThe Sheep Creek deposit is in the Totatlanika Schist near its contact with the Keevy Peak Formation (Nokleberg and others, 1994). The Totatlanika Schist ranges in age from Early Mississippian to Middle Devonian and consists mostly of felsic and mafic metavolcanic and metavolcaniclastic rocks (Wilson and others, 1998). The deposit is 200 feet thick and 2,000 feet long, and consists of isoclinally folded, stratabound lenses of massive sulfides in tuffaceous chlorite schist and chert (O'Connor and others, 1989). The sulfides are fine-grained sphalerite, galena, and pyrite. This deposit has high values of Sn, reported as either cassiterite or stannite. Channel sampling and grab samples contain up to 11% combined lead and zinc, and 10 grams of silver per ton. Zones up to 1 meter wide contain 1% tin (Nokleberg and others, 1994).
|Geologic map unit||(-148.28232566734, 63.9195539302683)|
|Mineral deposit model||Kuroko massive sulfide (Cox and Singer, 1986; model 28a)|
|Mineral deposit model number||28a|
|Age of mineralization||Mineralization is syngenetic with the Paleozoic host rocks.|
|Alteration of deposit||Alteration consists of sericitized schist in both the hanging and footwall of the deposit.|
|Workings or exploration||At least three drill holes to a maximum depth of 470 feet were completed in the 1970s (O'Connor and others, 1989). Channel sampling and grab samples contain up to 11% combined lead and zinc, and 10 grams of silver per ton. Zones up to 1 meter wide contain 1% tin (Nokleberg and others, 1994).|
|Indication of production||None|
|Reserve estimates||Based on limited data a tentative resource of 5.5 million pounds of tin has been identified (O'Connor and others, 1989). There are no estimates of base metal reserves.|
Bundtzen, T.K., Eakins, G.R., Clough, J.G., Lueck, L.L., Green, C.B., Robinson, M.S., and Coleman, D.A., 1984, Alaska's mineral industry, 1983: Alaska Division of Geological and Geophysical Surveys Special Report 33, 56 p.
Cox, D.P., Light, T.D., Csejtey, Bela, Jr., and Campbell, D.L., 1989, Mineral resource assessment map of the Healy quadrangle, Alaska: U.S. Geological Survey Miscellaneous Field Studies Map, MF-2058-A, 1 sheet, scale 1:250,000.
Nokleberg, W.J., and (seven) others, 1994, Metallogeny and major mineral deposits of Alaska and Metallogenic map of significant metalliferous lode deposits and placer districts of Alaska, in Plafker, G. and Berg, H.C., eds., The Geology of Alaska: Geological Society of America, DNAG, The Geology of North America, Vol.. G1, p. 855-904, Plate 11, scale 1:2,500,000.
Nokleberg, W.J., Bundtzen, T.K., Berg, H.C., Brew, D.A., Grybeck, D.J., Robinson, M.S., Smith, T.E., and Yeend, W., 1987, Significant metalliferous lode deposits and placer districts of Alaska: U.S. Geological Survey Bulletin 1786, 104 p., 2 plates, scale 1:5,000,000.
O'Connor, W.K., Dahlin, D.C., and Warner, J.D., 1989, Characterization of the Sheep Creek Pb-Zn-Ag-Sn prospect, north-central Alaska Range: U.S. Bureau of Mines Report of Investigations 9256, 21 p.
Wahrhaftig, Clyde, 1970, Geologic map of the Healy D-3 quadrangle: U.S. Geological Survey Geologic Quadrangle Map GQ-805, scale 1:63,360.
|Reporters||N. Van Wyck (Stevens Exploration Management Corporation)|
|Last report date||4/7/2000|